Adolescent Presentation of Unicornuate Uterus With Non-Communicating Rudimentary Horn: A Rare Cause of Severe Dysmenorrhea

A 12‐year‐old girl from Pakistan presented to the obstetrics and gynecology clinic with complaints of severe cyclical lower abdominal pain for the past 5–6 months. The pain began following menarche at the age of 11 years, occurring during menstruation and lasting for the full 7 days of her menstrual cycle. It progressively worsened with each cycle, significantly intensifying over the last 3 months. The pain radiated to the lower back and entire abdomen, was temporarily relieved by painkillers, and was not influenced by the time of day. There were no associated symptoms such as nausea, vomiting, or fever. Her menstrual bleeding has progressively decreased over time, although her menstrual cycles remain regular in duration. She has no relevant family history or previous hospital admissions or surgeries. She was not taking any medications other than painkillers, which she discontinued 2 months ago. There is no history of known allergies or significant medical illnesses. On systemic examination, the patient had a soft, non‐pulsating, deep, non‐tender lower pelvic mass, with no fluid thrill or fluctuation. Despite this, the patient reported pain on touch during menstruation, though there were no signs of acute inflammation or tenderness at the time of examination. The rest of the systemic examination was unremarkable. An ultrasound of the pelvis (Figure  1 ) revealed a right hemi‐uterus with a non‐communicating left horn containing an endometrial cavity showing a shading artifact, indicating a blood‐filled cavity. The bilateral ovaries, fallopian tubes, uterus, and bladder appeared normal, with some fluid in the cul‐de‐sac. An MRI pelvis (Figure  2 ) was performed to confirm the diagnosis and plan treatment, showing an obstructed rudimentary horn of the uterus containing functional endometrial tissue. USG pelvis transverse view showing a normal uterine cavity with echogenic endometrial stripe (blue arrow), a fluid filled cavity/functional rudimentary horn likely containing blood(red arrow). Green arrow points towards the right ovary. (A) Axial T1, (B) Axial STIR, (C) Axial T2, (D) Coronal T2, (E) and (F) Sagittal T2. MR imaging findings showing a unicornuate uterus (red arrows) with its endometrial cavity communicating with the cervix and vagina along with a non communicating yet functional, endometrium lined left rudimentary horn (blue arrows) which seems to have been distending with blood(showing shading sign) but not communicating with the normal uterus (red arrows) or outside. Bilateral normal ovaries can be seen in the axial T2 image (green arrows). Unfortunately, the patient did not proceed with the recommended laparoscopic resection of the non‐communicating horn. Both financial constraints and her mother's reluctance to provide consent for the procedure were contributing factors. While the option of an open abdominal approach was also discussed, no surgical intervention could be carried out due to these challenges.

Nizra Amjad: conceptualization, data curation, investigation, writing – original draft, writing – review and editing. Ayesha Jamal: conceptualization, data curation, investigation, writing – original draft, writing – review and editing. Sama Ghaffar: conceptualization, data curation, investigation, writing – original draft, writing – review and editing. S. M. Salman Hassan: conceptualization, data curation, investigation, writing – original draft, writing – review and editing. Mudasira Habib: conceptualization, data curation, investigation, writing – original draft, writing – review and editing. Allahdad Khan: conceptualization, data curation, investigation, writing – original draft, writing – review and editing. Mohamed Antar: conceptualization, data curation, investigation, writing – original draft, writing – review and editing.

Informed consent for the publication of the patient's clinical information and imaging was obtained from the patient's guardian. The guardians emphasized the importance of maintaining the patient's confidentiality, ensuring that no personal identifiers would be disclosed in the publication.

Congenital uterine malformations, resulting from irregular Mullerian duct development, affect 1% to 10% of the general population, with increased prevalence (2%–8%) in women experiencing infertility and (5%–30%) in those with a history of miscarriage. Determining exact incidence is complicated by diverse diagnostic methods and classification systems [ 1 ]. While the unicornuate uterus is known among gynecologists, encountering the rare rudimentary functional horn with obstruction, arising from incomplete fusion of one Mullerian duct, is less common. The prevalence of such anomaly is 0.1%, 0.5%, and 2% in unselected, infertile, and miscarriage‐prone women, respectively [ 2 ]. Obstructed rudimentary horn in a unicornuate uterus commonly presents with dysmenorrhea, pelvic pain, and carries various obstetric risks including miscarriage, stillbirth, preterm birth, malpresentation, ectopic pregnancy, heavy bleeding, and placental issues, with maternal mortality between 6%–23%.

The authors declare no conflicts of interest.